Hello,
These are two very complementary techniques if taken to properly. The consideration being this: Linseed oil is not durable and will breakdown under exposure to ultra violet light and wash away, along with a good part of the carbon layer, within half a year when it is applied as a surface treatment out of doors.
Two things can mitigate this. One is to use the linseed oil as an impregnation but this means it must go into the wood. You can achieve this by adding turpentine or putting it on warm, (this all assuming you are using raw, warm or cold pressed linseed oil). The other alternative would be to add a pigment which will shield the oil from the sun's rays. And this is where the beauty of the two techniques you want to use comes in because you can use the residue from the charcoaling process as a pigment with the oil. Either sift the dust prior to mixing it with the oil or strain the oil afterwords and apply it as described above using a brush.
Greetings,
Don Wagstaff
Last edited by Cecile en Don Wa; 08/03/11 02:21 PM.